/Engine/Source/Runtime/Engine/Classes/Particles/FXBudget.h
Returns the global FX time / budget ratio but adjusted in various ways better drive FX scaling. e.g. Usage goes up in line with the real usage but can fall only at a set rate. Useful to avoid FX flipping on/off if their cost is tipping the usage over the budget.
static [FFXTimeData](API\Runtime\Engine\Particles\FFXTimeData) GetAdjustedUsage()